A fluid flow process (flow process) includes any process that involves the flow of fluid through pipes, ducts, or other conduits, as well as through fluid control devices such as pumps, valves, orifices, heat exchangers, and the like. Flow processes are found in many different industries such as the oil and gas industry, refining, food and beverage industry, chemical and petrochemical industry, pulp and paper industry, power generation, pharmaceutical industry, and water and wastewater treatment industry. The fluid within the flow process may be a single phase fluid (e.g., gas, liquid or liquid/liquid mixture) and/or a multi-phase mixture (e.g. paper and pulp slurries or other solid/liquid mixtures). The multi-phase mixture may be a two-phase liquid/gas mixture, a solid/gas mixture or a solid/liquid mixture, or a gas entrained liquid. The fluid may also be a three-phase mixture such as a gas/liquid/liquid mixture or a gas/liquid/solid mixture.
In certain flow processes, such as those found in the oil and gas industries, it is desirable to separate the liquid (e.g., oil and/or water) and the gas (e.g., air) components of the fluid. This is typically accomplished using a separator, which is an item of production equipment used to separate liquid components of the fluid stream from gaseous components. The liquid and gas components flow from the separator in separate legs (pipes), with the leg containing the gas component referred to as the “gas leg” and the leg containing the liquid component referred to as the “liquid leg”. Each of the legs typically includes a flow meter to determine the volumetric flow rate for each of the gas and the fluid components, respectively, wherein the volumetric flow rate for the gas leg is commonly measured using an orifice plate.
As is well known in oil and gas production, the carry-over of liquid into the gas leg of the gas/liquid separator commonly occurs, wherein the liquid typically takes the form of a mist comprised of small liquid droplets, commonly known as wet gas. This is undesirable because the liquid carry-over can result in a host of undesirable events depending in large part on the degree of carry-over that takes place. As such, in order to minimize the amount of liquid carry-over most separators have mist catchers designed to recover the liquid carried over. Unfortunately however, accurate measurements of the amount of liquid carry-over have not been obtainable because there currently exists no devices and/or methods for accurately determining the amount of liquid carried over into the gas leg. As such, there is a need for an apparatus and method to accurately measure the amount of liquid carry-over as well as the flow rates of the liquid and gas phases of the wet gas flow.
A difficulty that often occurs when taking measurements relevant to fluid flows within conduits such as pipes results from the fact that it is often necessary to have sensors within the flowing fluid. This increases the potential for difficulties associated with leaks as well as weakening the conduit or pipe. This can be particularly problematic when it is necessary to measure flow characteristics and parameters on existing pipes. It may be difficult to make modifications to such systems.
In addition, it may not be feasible, or be too costly to shut a system down to make these modifications.
Based on the foregoing, it is the general objection of the present invention to provide an apparatus and method for determining wetness in a gas flow that improves upon or overcomes the problems and drawbacks associated with the prior art.